1 cup frozen spinach, thawed and excess water squeezed out
2 1/2 cups shredded mozzarella, divided
1/4 cup butter
1/4 cup flour
3 1/2 cups milk
Cook the kabocha squash: Preheat the oven to 400 degrees. Cut the squash in half and scoop out the seeds. Place cut side down on a baking sheet and bake 45 minutes, until very soft. Allow to cool, then scoop out.
In two separate bowls, add 1 cup of ricotta. In one bowl, add the squash and mash to combine. In the other bowl of ricotta, add spinach, salt and 1/2 cup mozzarella and stir to combine.
Boil a large pot of salted water and cook the lasagna noodles for 7 to 8 minutes, until al dente. Stir the noodles occasionally to keep them from sticking together. Drain the noodles in a colander and then lay them flat on a baking sheet so they don’t stick together in a clump.
Make the bechamel: Heat a saucepan over medium heat. Add the butter and allow to melt. Stir in the flour and continue cooking for 2 minutes, while stirring. Whisk in the milk a little at a time and bring to a simmer. Cook for 10 minutes, stirring frequently. Season with salt and pepper.
Assemble the lasagna: Add a ladleful of bechamel onto the bottom of a 9 by 13 glass baking dish. Top with noodles to cover, and then the ricotta squash mixture. Pour 1/2 cup more sauce over the top and then add more noodles to cover. Next spread the ricotta spinach mixture and then 1/2 cup more sauce. Top that with noodles. Spread the remaining sauce over the top and then the remaining 2 cups of cheese.
Cover with foil and bake for 30 minutes, remove foil and bake another 15 minutes.